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/* Copyright (C) 1998, 1999 Cygnus Solutions
This file is part of libgcj.
This software is copyrighted work licensed under the terms of the
Libgcj License. Please consult the file "LIBGCJ_LICENSE" for
details. */
package java.io;
/**
* @author Warren Levy <warrenl@cygnus.com>
* @date October 7, 1998.
*/
/* Written using "Java Class Libraries", 2nd edition, ISBN 0-201-31002-3
* "The Java Language Specification", ISBN 0-201-63451-1
* plus online API docs for JDK 1.2 beta from http://www.javasoft.com.
* Status: Believed complete and correct
*/
public class ByteArrayInputStream extends InputStream
{
/* An array of bytes provided by the creator of the stream. */
protected byte[] buf;
/* Position of the next byte in buf to be read. */
protected int pos;
/* The currently marked position in the stream. */
protected int mark;
/* The index in buf one greater than the last valid character. */
protected int count;
public ByteArrayInputStream(byte[] buffer)
{
this(buffer, 0, buffer.length);
}
public ByteArrayInputStream(byte[] buffer, int offset, int length)
{
buf = buffer;
count = offset + length;
if (count > buf.length)
count = buf.length;
pos = offset;
// TBD: What should we do if pos is neg. or > count? E.g. throw exc. or:
// if (pos < 0 || pos > count)
// pos = 0;
mark = pos;
}
public synchronized int available()
{
return count - pos;
}
public synchronized void mark(int readAheadLimit)
{
// readAheadLimit is ignored per Java Class Lib. book, p.220.
mark = pos;
}
public boolean markSupported()
{
return true;
}
public synchronized int read()
{
if (pos < 0)
throw new ArrayIndexOutOfBoundsException(pos);
if (pos < count)
return ((int) buf[pos++]) & 0xFF;
return -1;
}
public synchronized int read(byte[] b, int off, int len)
{
/* Don't need to check pos value, arraycopy will check it. */
if (off < 0 || len < 0 || off + len > b.length)
throw new ArrayIndexOutOfBoundsException();
if (pos >= count)
return -1;
int numBytes = Math.min(count - pos, len);
System.arraycopy(buf, pos, b, off, numBytes);
pos += numBytes;
return numBytes;
}
public synchronized void reset()
{
pos = mark;
}
public synchronized long skip(long n)
{
// Even though the var numBytes is a long, in reality it can never
// be larger than an int since the result of subtracting 2 positive
// ints will always fit in an int. Since we have to return a long
// anyway, numBytes might as well just be a long.
long numBytes = Math.min((long) (count - pos), n < 0 ? 0L : n);
pos += numBytes;
return numBytes;
}
}
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